Such as this one below applying to BOGO’s:
Buy 1, Get 1 Free Coupons
The guidelines below are to be followed in addition to the General Guidelines listed above.
When items are featured in a Buy 1 Get 1 Free promotion, at least one product needs to be purchased. A maximum of one BOGO coupon is permitted per two qualifying items in a BOGO offer.
Coupons may not be applied against any free item received in any offer
And this one is a sad day as well:
Walgreens will not accept coupons that exceed the selling price of an item and no cash back is ever provided in exchange for any coupons
You can read the rest HERE